++
++
++
++
Rabies virus is rapidly destroyed by
++
++
++
(A) Ultraviolet radiation
++
++
(B) Heating at 56°C for 1 hour
++
++
++
++
++
++
++
++
++
Prions are readily destroyed by
++
++
++
++
++
++
++
++
++
++
++
++
++
++
The presence in neurons of eosinophilic cytoplasmic inclusion bodies, called Negri bodies, is characteristic of which of the following central nervous system infections?
++
++
++
++
++
++
++
(C) Subacute sclerosing panencephalitis
++
++
(D) New variant Creutzfeldt-Jakob disease
++
++
(E) Postvaccinal encephalitis
++
++
++
Which of the following statements about rabies vaccines for human use is true?
++
++
++
(A) Contain live, attenuated rabies virus
++
++
(B) Contain multiple antigenic types of rabies virus
++
++
(C) Can treat clinical cases of rabies
++
++
(D) Can be used for postexposure prophylaxis
++
++
(E) They are associated with Guillain-Barre syndrome
++
++
++
A 22-year-old man is a resident of a small town near London. He likes to eat beefsteak. He develops a severe progressive neurologic disease characterized by psychiatric symptoms, cerebellar signs, and dementia. Probable bovine spongiform encephalopathy (BSE) is diagnosed. New variant Creutzfeldt-Jakob disease in humans and BSE appear to be caused by the same agent. Which of the following statements is true of both diseases?
++
++
++
(A) Immunosuppression of the host is a predisposing factor.
++
++
(B) It is an immune-mediated degenerative neurologic disorder.
++
++
(C) There is a long incubation period (months to years) from time of exposure to appearance of symptoms.
++
++
(D) The agent is recoverable only from the central nervous system of an infected host.
++
++
(E) The interferon response persists throughout the incubation period.
++
There is a high-titer antibody response toward PrPSc protein of the agent.
++
++
++
Rabies virus has a wide host range and the ability to infect all warm-blooded animals, including humans. Which statement about the epidemiology of human rabies is true?
++
++
++
(A) Africa accounts for the majority of rabies fatalities.
++
++
(B) Dog bites cause most cases of human rabies in England.
++
++
(C) Domestic animals are the source of most human rabies in the United States.
++
++
(D) Human-to-human rabies transmission places medical personnel at serious risk.
++
++
(E) Bat rabies has caused most human rabies cases in the United States since the 1990s.
++
++
++
Infectious scrapie agent can be detected in amyloid plaques in infected brains of sheep and hamsters. The genome of the infectious agent is characterized by which of the following nucleic acid types?
++
++
++
(A) Negative-sense, single-stranded RNA
++
++
(B) Small interfering RNA, smallest known infectious RNA
++
++
(C) DNA copy of RNA genome, integrated in mitochondrial DNA
++
++
(D) Single-stranded, circular DNA
++
++
(E) No detectable nucleic acid
++
++
++
A 49-year-old man visited a neurologist after 2 days of increasing right arm pain and paresthesias. The neurologist diagnosed an atypical neuropathy. The symptoms increased and were accompanied by hand spasms and sweating on the right side of the face and trunk. The patient was admitted to the hospital the day after developing dysphagia, hypersalivation, agitation, and generalized muscle twitching. Vital signs and blood tests were normal, but within hours the patient became confused. The consulting neurologist suspected rabies. Rabies immune globulin, vaccine, and acyclovir were administered. The patient was placed on mechanical ventilation the following day. Renal failure developed, and the patient died 3 days later. Rabies test results were positive. The patient’s wife reported the patient had suffered no bites by dogs or wild animals. The most likely explanation for treatment failure is
++
++
++
(A) The rabies test results were falsely positive and the patient did not have rabies.
++
++
(B) Treatment was initiated after the onset of clinical symptoms of rabies.
++
++
(C) The vaccine was directed against dog rabies and the patient was infected with bat rabies.
++
++
(D) The rabies immune globulin should not have been administered as it interfered with the vaccine.
++
++
(E) Interferons—and not the treatment regimen administered—are the treatment of choice once rabies symptoms develop.
++
++
++
Which of the following animals is most commonly reported rabid in the United States?
++
++
++
++
++
++
++
++
++
++
++
++
++
++
A runner reports an “unprovoked bite” from a neighborhood dog. The dog was captured by local animal control authorities, and it appears healthy. What is the appropriate action?
++
++
++
(A) Confine and observe the dog for 10 days for signs suggestive of rabies.
++
++
(B) Begin postexposure prophylaxis of the bitten person.
++
++
(C) Immediately euthanize the dog.
++
++
(D) Because canine rabies has been eliminated in the United States, dog bites are no longer an indication for postexposure prophylaxis, and no further action is needed.
++
++
(E) Test the dog for rabies antibody.
++
++
++
The slow virus disease that most clearly has immunosuppression as an important factor in its pathogenesis is
++
++
++
(A) Progressive multifocal leukoencephalopathy
++
++
(B) Subacute sclerosing panencephalitis
++
++
(C) Creutzfeldt-Jakob disease
++
++
++
++
++
Scrapie and kuru possess all of the following characteristics except
++
++
++
(A) A histologic picture of spongiform encephalopathy
++
++
(B) Transmissibility to animals associated with a long incubation period
++
++
(C) Slowly progressive deterioration of brain function
++
++
(D) Prominent intranuclear inclusions in oligodendrocytes
++
++
++
A 5-year-old boy in San Francisco reaches into a car to pet another family’s dog and is bitten on the finger. Six weeks after the bite, the child develops fever, headache, and a seizure. He becomes combative and hallucinates. What is the best diagnostic test to perform on the patient to rule in rabies as a cause of his illness?
++
++
++
(A) Detection of serum antirabies antibody
++
++
(B) Culture of cerebrospinal fluid for virus
++
++
(C) Direct fluorescent antibody stain of a biopsy from the nape of the neck
++
++
++
++
(E) Cerebrospinal fluid antirabies antibody
++
++
++
Each of the following statements concerning rabies and rabies virus is correct except
++
++
++
(A) The virus has a lipoprotein envelope and single-stranded RNA as its genome.
++
++
(B) The virus has a single antigenic type (serotype).
++
++
(C) In the United States, dogs are the most common reservoir.
++
++
(D) The incubation period is usually long (several weeks) rather than short (several days).
++
++
++
A 20-year-old man, who for many years had received daily injections of growth hormone prepared from human pituitary glands, develops ataxia, slurred speech, and dementia. At autopsy the brain shows widespread neuronal degeneration, a spongy appearance due to many vacuoles between the cells, no inflammation, and no evidence of virus particles. The most likely diagnosis is
++
++
++
++
++
(B) Creutzfeldt-Jakob disease
++
++
(C) Subacute sclerosing panencephalitis
++
++
(D) Progressive multifocal leukoencephalopathy
++
++